i swam competiavely since i was a kid for years before startin thaiboxing + even now iam still a swimming teacher.flippers are used to strenghtin the legs if you hav a weak kick or want to build ur kick up more.if ur doing a legkick set with them on you should do more sets or the same on a faster time because you will go alot faster with them on.another good kick drill is standing out of ur depth cross ur arms using just leg kick to keep ur head + shoulders out of the water every1 will be differnt to the amount they can do.it doesnt matter what u do in the pool use the clock time ur sets,rest + keep track of what you do.every week increase the number of sets or the speed slightly so you get fitter.
ah realy good drill for ur lungs + breathing(the best i tink)is spriting as fare as you can without breathing(just take 1 big 1 at the start).or trying to swim as far as u can under water.it forces ur lungs to get bigger.wait till you get ur breath back + go again.do about 4 lenghts to start with.you will see the differnce down the gym inbetween rounds.BE WARNED this can be Dangerous some people have been knowin to faint + there have been cases of death.so if you are doing it DONT do it on ur own,make sure u tell the lifeguard what you doing,most of all when you realy want to take the breath take 1.the death cases were the 1s that were trying to break records en that + pushed themselfs to hard.